Researchers had good news about some of the most difficult-to-treat breast cancers on Thursday. They found that pre-treating young women with a rare form of breast cancer can help them survive better down the road.

Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

It’s a rare bit of hope for young women, those under 35, who get breast cancer out of the blue – especially because they are far more likely than older women to have a hard-to-treat type of breast cancer called triple negative breast cancer.

The study, presented at the San Antonio Breast Cancer Symposium, showed that the pre-treatment, called neoadjuvant chemotherapy, before surgery greatly improved the chances that a woman’s tumor would be completely killed. The pre-treatment approach is used in several forms of cancer to shrink and contain a tumor before a surgeon goes in to cut it out.

It worked best in the youngest women with triple-negative cancer – a surprising finding.

“It is extremely encouraging to know there is a very simple technique that can make a really big difference in terms of coming out the other end with no disease,” said Lori Redmer, former executive director of the Triple Negative Breast Cancer Foundation.

For the study, Dr. Sibylle Loibl of the University of Frankfurt in Germany and colleagues looked at data from eight German studies involving more than 8,900 women. They included 700 young women with the triple-negative form of breast cancer.

“Young women with breast cancer are rare, and some data indicate that their prognosis is worse than it is for older women,” said Loibl. “This is not only because their tumors tend to be more aggressive, but because breast tumors that arise in women who are young seem to be a special biological entity.”

Most breast cancer is driven by one of three causes – the hormone estrogen, another hormone called progesterone, or a gene called human epidermal growth factor receptor 2 (HER2). Triple negative isn’t caused by any of these – and it isn’t helped by the many targeted drug treatments that have been developed to fight the other three causes.

Women with triple negative cancer have to take old-fashioned toxic chemotherapy drugs, with all their unpleasant side-effects. Worse, because triple-negative cancer is more likely to strike young women, they aren’t checking for cancer the way older women are, they aren’t getting regular mammograms, and they often don’t find the tumors until they are large and have spread.

That was the case with Redmer, who was 42 when she was diagnosed in 2010 – with three young children. Her first symptom was severe pain, and her cancer had already spread by the time she was diagnosed. “It is an extremely aggressive, fast-moving tumor,” Redmer said in a telephone interview. “It is a terrifying diagnosis.”

Because her tumor was so large and painful, Redmer didn’t get the pre-treatment with chemotherapy.

Redmer’s cancer has returned and, at the age of 45, she’s had to quit her job with the foundation to concentrate on treatment. That’s very often the case with aggressive cancers.

In Loibl’s study, just under a quarter of the women under 35 with breast cancer got what is termed a “pathological complete response” when they got neoadjuvant chemotherapy. That means the cancer looked gone.

Dr. Michaela Higgins, an oncologist at Massachusetts General Hospital in Boston, says that’s known to be good news. “Those who obtain a pathological complete response are more likely to survive than those who do not,” Higgins said in a telephone interview.

Twenty-five percent may not look good, but among older women, who usually had other types of cancer, the neoadjuvant therapy didn’t help even that much. Just over 15 percent of them had this positive result, Loibl’s team found. The findings reinforce the idea that breast cancer that hits young women is a different disease from the type that affects older women, and must be treated differently.

“The only plus side to having triple negative breast cancer is it does respond better to chemotherapy,” Higgins said. She said these new findings will reinforce the idea that doctors should treat these young women first with chemotherapy, then with surgery.

Patients may wonder if it’s worth going through the pain of chemotherapy, but Higgins said especially for younger patients, it is. “They have more years of life at stake,” she said.

Breast cancer is the second-leading cancer killer of women, after lung cancer. The American Cancer Society projects that 226,870 women will be diagnosed with breast cancer this year and that 39,510 will die of it.

In the United States, 93 percent of women with Stage 1 breast cancer survive for at least five years, but this falls to 15 percent for women with stage 4 – the type that has spread widely.

“To have some good news like this, that can make a difference, is really encouraging,” said Redmer.